[请教]BIOS地址映射?

暴雪

原512K的ROM，现换了一个1M的ROM，windows下在 0xFFF0 0000~0xFFF7 FFFF 可以看到追加的512K的内容。
; Q: G9 I" ]7 S, q4 m. Z但在启动计算机时(BIOS没有初始化计算机），无法访问追加的512K的ROM。
; ?' _( i4 f. o9 H9 Y9 y* m0 K+ w(可以访问原512K的ROM 0xFFF8 0000~0xFFFF FFFF)

2 h/ H. K/ m9 k6 C' J& v3 G我的计算机用的是intel的ICH7南桥。
在手册上
" N2 L* p9 Y$ E# r( G# BFWH_SEL2—Firmware Hub Select 2 Register (LPC I/F—D31:F0)
FWH_70_IDSEL — R/W. IDSEL for two, 1-M Firmware Hub memory ranges.
+ L3 x# U% ]% p/ Z, d* C" D" eThe IDSEL programmed in this field addresses the following memory ranges:
' B: Y9 q: @0 }( \FF70 0000h – FF7F FFFFh
FF30 0000h – FF3F FFFFh
# A& }* y' ^& J" x在这里 IDSEL 如何理解。
/ R$ X' e1 b$ U( kFWH_DEC_EN1—Firmware Hub Decode Enable Register
(LPC I/F—D31:F0)
# G$ {( {$ |) r/ B( C6 W) q- _- LFWH_70_EN — R/W. Enables decoding two 1-M Firmware Hub memory ranges.
7 P. O# N# i) z4 A6 b0 = Disable.
1 = Enable the following ranges for the Firmware Hub
% i# J; H, T: }( x6 ~( G( @6 oFF70 0000h – FF7F FFFFh
1 M3 u- e+ _$ p9 A# l" E+ w! ]FF30 0000h – FF3F FFFFh
" u1 Y5 ?* x, v! E( x6 o. E除了上面的数据区域，还有其它的数据区域控制ROM到内存地址的映射吗？
5 t" j  j2 E7 a4 F% Y7 k
谢谢大家了！！！

xtdumpling

IDSEL是LPC spec的一个信号(Device Select),
, H; Z, I6 P. o2 H+ b9 U1 {2 o" t, D8 mThis one clock field is used to indicate which of multiple Firmware components is being selected.
The four bits transmitted over AD[3:0] during this clock are compared with values strapped onto
pins on the Firmware component. If there is a match, the Firmware component will continue to
9 t. i% m: e( C6 o8 Xdecode the cycle to determine which bytes are requested on a read or which bytes to update on a
5 p+ v6 m' Q3 R8 swrite. If there isn’t a match, the Firmware component may discard the rest of the cycle and go into
9 z4 n4 a) [* d* W: Va standby power state.
! y8 T& W. d& f9 g' T& }
详见LPC spec:
( m+ ~2 c" k2 D) g+ B. n2 ohttp://www.intel.com/design/chipsets/industry/25128901.pdf

在ICH 7 中似乎就这几个吧(FWH_SEL1,FWH_SEL2,FWH_DEC_EN1,BIOS_CNTL),据我现在知道的.